Conventionally, apparatuses are known for continuously delivering a sheet from an original material roll formed by winding the sheet.
When a remaining sheet amount of the original material roll becomes small in an apparatus of this type, for example, a joining operation of sheets such as that shown in FIG. 29 to FIG. 32 is performed.
Specifically, in order to perform the joining operation, as shown in FIG. 29, an original material roll (hereinafter, referred to as a standby-side original material roll) R2 which stands by for delivery of a sheet W is installed in advance adjacently to an original material roll (hereinafter, referred to as a delivery-side original material roll) R1 which delivers the sheet W.
As shown in FIG. 30, when a remaining amount of the sheet W of the delivery-side original material roll becomes small, an end section of the sheet W is retrieved from the standby-side original material roll R2 and an adhesive (for example, a tape T) is affixed to the end section of the sheet W.
Next, as shown in FIG. 31, using the tape T, the end section of the sheet W of the standby-side original material roll R2 is connected to an intermediate section of the sheet W of the delivery-side original material roll R1 and the sheet W of the delivery-side original material roll R1 is cut at an upstream position (a position denoted by a triangle in FIG. 31) relative to the tape T.
Accordingly, as shown in FIG. 32, tension applied to the sheet W on a downstream side of both original material rolls R1 and R2 is applied via the tape T to the sheet W of the standby-side original material roll R2, and the sheet W is delivered from the standby-side original material roll R2. In other words, the standby-side original material roll R2 performs a role of a next delivery-side original material roll R1.
As an apparatus for automatically performing the joining operation described above, for example, an apparatus described in Japanese Unexamined Patent Publication No. H7-101602 is known.
The apparatus described in Japanese Unexamined Patent Publication No. H7-101602 includes: a roll holding unit which holds a delivery-side original material roll and a standby-side original material roll; a joining unit which joins a sheet of the standby-side original material roll to a sheet of the delivery-side original material roll; and an XY mobile robot which retrieves an end section of the sheet of the standby-side original material roll and which guides the end section to the joining unit.
The XY mobile robot includes a head which is movable between a retrieval position of the sheet of the standby-side original material roll that is set in the roll holding unit and the joining unit.
The roll holding unit includes a mechanism which, after the sheet of the standby-side original material roll is joined to the sheet of the delivery-side original material roll, moves the standby-side original material roll to a sheet delivery position set in advance and, at the same time, moves the delivery-side original material roll to the retrieval position. Subsequently, the delivery-side original material roll having been moved to the retrieval position is detached and a new standby-side original material roll is attached to the roll holding unit.
However, the apparatus described in Japanese Unexamined Patent Publication No. H7-101602 requires a mechanism for interchanging positions of the standby-side original material roll and the delivery-side original material roll, and the mechanism is large in accordance with a diameter of an unused original material roll.
Therefore, a structure of the roll holding unit becomes complex and a size of the roll holding unit increases.